Musical instrument



Feb. 24, 1931;

A. D. LOMAN. JR

MUSICAL INSTRUIENT Filed Sept. 10. 1929 0 F/af- C F/af C Sher o 0 5/2090 l NVE Nron; 91M10 JIM [amt/g, Jpn/0f ATTORNEYS.

Patented Feb. 24, 1931 UNITED STATES ABRAHAM DIRK LOMAN, JR., OF AMSTERDAM, NETHERLANDS MUSICAL INSTRUMENT Application filed September 10, 1929, Serial No.

The present invention relates to a novel musical instrument.

In order to obtain a perfect comprehension of the device it will be necessary to state a few of the laws and rules of the production and propagation of sound.

The pitch of a tone depends on the frequency of vibrations producing said tone.

The difference in pitch of two tones depends on the proportion (not the arithmetical dili'erence) that the frequency of vibration producing one tone bears to that producing the other tone; and, as far as such proportion has a musical meaning, it is called the interval between the two tones.

The usual succession of notes between two tones which are distant from one another by a whole octave, is called a scale. The most usual scales are those of major and minor, every one of which comprises eight tones be tween which there are accordingly seven intervals. These intervals are not alike; there are five so-called major seconds and two socalled minor seconds. When dealing with keyboard instruments, the first named are also called whole tones, the latter being called halftones. Now, in the case of key-board instruments, the octave is divided into 12 equal intervals which thu correspond nearly to the half-tones mentioned (2X 5 plus 2 12).

This tuning which is called equal temperament is adapted to organs, and piano-fortes. The.dil'lercmzes in' height oi? tone originated by this practical rule, compared with actual musical performances, are so trifling as not to hurt a musically trained car.

In the drawing accompanying this specification,

Fig. 1 is a diagrammatic view illustrating the notes of an octave;

Fig. 2 is a diagrammatic view illustrating a musical scale to which the features of the present invention are applied; and

Fig. 3 is a central vertical section of one of the sirens employed in carrying out the invention.

As is well known, the ratio of vibrations between any two tones one of which is one octave higher or lower than two others, is equal to 2. That distance being divided into twelve 391,583, and Germany September 12, 1928.

equal intervals (proportion numbers), each interval, namely that of a half tone, is equal to For the sake 0 f facility let us represent it by W, so that 2 =W. Then, if the frequency of vibrations of the first tone of an octave be called 1, the frequencies coming next will be respectively represented by 1 WV W W WV" W and 2 It is obvious that all of these frequencies of vibrations, except the first and the last, are surd numbers, i. e. roots which cannot be represented in the shape of integral numbers nor as vulgar or decimal fractions. Therefore, they cannot be practically utilized, as only rational quantities can be dealt with.

WVhen tuning an organ or a piano-forte one must necessarily rely on the skill of the tuner who has to provide for introduction of such ascending gradation into the organ reeds or into the strings.

A second drawback resides in the fact that in course of time, in a pianoforte, one or more of the strings may sink lower than the others, for instance, as a result of having been subjected to harder duty, and this causes the entire system of equal temperament to become unfit for service. On the other hand, tuning of an organ can be very easily disturbed through temperature changes (warm or cold) or as a result of the hygrometrical condition of the air.

These drawbacks which are indeed very serious ones, will be avoided, as will be ex plained hereinafter, by the use of the novel instrument described herein. It is based upon the same principle as a siren, whereby any volume of sound can be developed and music can be emitted so as to be heard a number of kilometres away.

As is known, the height of pitch of a siren depends on two factors, namely, the number of revolutions per unit of time imparted to it, and the number of openings provided upo a peripheral circle (or a cover circle) of the siren, which corresponds with a like number of openings in a stationary wall; the product of these two numbers is equal to the amountof thrusts of air originated.

i a basis for building up 'all'the Now, when trying to build up a musical instrument whose tones are to be obtained by means of sirens to be tuned with respect to one another in accordance with equal tem- 5 perament, a diliiculty arises in that irrational numbers of the equal temperament cannot possibly be expressed in the shape'o'f rational tion:

al numbers are replaced by rational fractions which have these features;

(1) they are so :little'idifierent from the irrational values'tha't nobod yflslear can detect the; difference even if liighlyntmined, and v ,(2) 'the n-uinerators denominators are such that theycan berrealized-as anumber of orifices provided in asiren or asthenumj ber ,of teeth ofa gear'wheel'or acha'inwheel adapted for 'tran'slnitting motion between shaftst" so B, Every-siren is so constructed as toemit,

at Will, ;t'\vo tones, and, as;a result, a-Wv'hole octave can be emitted by meansofj six sirens only. r a

of two notes between wliic'h there'arejthree fraction 44/37'which1 is equ'alto ,1i189'19 As, the difference Vbetweenj 1118921 and 1.18919 islessflthan 0.002 per cent, itca'n never be detected even'h v, a high yftrain'ed ear.

This interv'al of 44;: 37 has 'been t'aken as these having two' rojwswl'iich have i s lv 37 and M: orifices those in each row'to be opened or closed attheoperatorswill.

Every siren will thus bring outa minor third. i-Therre'main'ing irrational values are also made to correspond to rational, values, nan 1'ely,fin respect of the number of revolutions of the various sir en slia'fts. I In the embodiment chosen as an example 5 and shownin Fig. 2,, ithemain shaft of the musical instrument istlie "shaft of the fourthsiren'to which thenecessary velocity ,is imarted to cause it to'emit'the notes A and C. henever'this shaft is caused to revolve at the rate of 1:2 revolutions per second, the low est tone, ofthe siren is given-a frequency of fvibration equaljto 37x12, or 444, which is little more than the normal A for which the international:numberc h.a,s;been stated as 435.

And, by slightly reducing'the velocity of the H Novv,;these drawbacks areeliminated in the following mann'erbythis' present 'mven- To this ef'fe ct, the interval oi the minor ztrainediear. third has beenstarted from the dis't'ance 5 t v, a i, v

i the veld' calculatedhthat the .decn

shaft provided such number he kept constant,

for the other sirens will rotate always at a certain ratio dependent on the number of theirrevolutions with respect to those of the siren located upon the main shaft.

In the embodiment shown in' Fig. 2, the

octave has been assumed to start from middle D sharp and to run on to the-next Dga'bove,

each of the six sirens emitting both tones ina i A, By anvaccurate,calculationthe rratipndicated'by the notes in Fig. i

The veloc ty of rotation of the shai'tsof the five remaining sirens is obtained in the st-he two tones D sharp and F sharp.

As there are six half tones between D sharp and-A, the interval D 'sharpzA can be represented by liVV. Calculation will show that this inter :11 ;becomes equal'to 0.707107 This irr 'o'nal ratio can be replaced byvthe rational i lction l '{0/99 which corresponds to the: decimal fraction 0.70'1071 "Sosiight a difference cannot be detected even by th'e inost"highly 'One must accordinglyobtain y; desired for the, lrst shaft by meshing with a toothed iv I teeth be-placedjupon themain shaft. It will be" explained herern'a fter' how this transmission and those followin can be rendered st ll easier.

Titesecond sir ew illiis siren omits the two 7 tones E and G." Asthere are llillf-iOllQS'bG- tween and A, the interval E :A'fcan be representedjby ,lzVVfi It has beenfcalcu lated that thisdnterval 'b com dual to It seenis'that t irrational ratiocan be: replaced by the "traction 221/295 which corresponds to "the decimal i ra'cl'ion Itwill be more thoroughlyexplainedliereinafter how the ratio 221-: 295- beieasily' arrived at, .without the 11ecessity-'ot'; using gears with a largenumber out-teeth. i 5

ThOL hZ Td sweat. This siren-emitsithe twc tones Band G sharp. fBince there are halftones between "F ja'nd Afthe men-Wynn 7 can be represented by WV? 'lt ha's 'been Al iractioirf becomesequal to 0.793701 tional ratio canbe replaced; by. f /63 the decimal value 10 'vvhic'li 1 0,793651. .1 The fifth vsir 7n, 'lhis siren enii-ts 'jtones A sharp and sharp'. i-.A's thereis r half-tone between A sharp and A, the inter.-

:the two i val A sharp A can be represented by VVzl. It has been calculated that this interval becomes equal to 1.059463 This irrational ratio can, in its turn, be replaced without giving rise to any trouble, by the fraction 196/185, the decimal value of which is 1.059 160.

The simt/z sirens-mus siren emits the two tones B and D. As .there are two half-tones between B and A, the interval B:A can be represented by WV zl. It has been calculated that this interval becomes 1.12246 This irrational ratio can, without difliculty, be replaced by the fraction 59/49, the decimal value of which is 1.12245.

The ratios for the number of revolutions of the six shafts can be represented respectively by:

/99 221/295 50/63 1 196/185 and 55/49 This result is diagrammatically shown in F ig. 2.

It has been experienced that, when dealing with such great speeds as must be applied here, the teeth of the chain-wheels should, preferably, not number less than 12 and not more than 24; and, in the case of gear-wheels, no wheel should have less than 50 teeth or so; if they have a substantially greater number of teeth, some. of them become unlit for service owing to the considerable mass of those whee-ls. Furthermore, experience teaches us that, in the case of greatspeed, chain-wheels are better than gear-wheels as their operation is more resil ient, on account of which it requires less power; therefore, it is advisable to use chainwheels whenever possible.

All of the above named transmissions can be obtained without difliculty by resorting to double transmission consisting either of two pairs of chain-wheels or of one such pair and a gear-wheel-pair; all of these chain-wheels and gear-wheels will be in compliance with the requirements as above stated.

This is obvious from the following statement wherein the pairs of chain-wheels are designated by (I and the pairs of gear-wheels by G:

The sirens can be constructed in various ways. A feature of an embodiment consists in a drum which is rotatably mounted inslde a stationary drum, these two drums fitting snugly one within the other and each having a pair of rows of openings containing respectively 37 and 44 orifices so placed as to permit coincidence of the like rows in both drums. Externally, round each of the rows of openings in the stationary drum there is a ring bored with a number of orifices equal to those of the drum it surrounds; each ring is connected with a key whereby rotary motion round thestationary drum in the plane of the orifices may be imparted to the ring, with the result that both rows of orifices provided in the stationary drum can be, opened or closed at will.

This is shown in Fig. 3, where a is the stationary drum provided with two rows of openings designated by h and g and having respectively 37 and 44 orifices. Another drum 7) fits inside the first one, and is capablr of rotation therein, this second drum Z) having rows containing the same number of openings placed at the same height. The drum 1) is secured to a shaft 0 for rotation therewith. Round the other drum a and in front of tin rows of openings there are rings 6 and d which are, to some extent, let into the drum a so that they can move in a fixed path. These rings are provided with the same number of orifices as the rows they surround; it is therefore, possible, by shifting the rings, to open or close to any extent and simultaneously all of the orifices pertaining to either row. Each ring is connected through an intermediate gearing with a key; the instrument can accordingly be played upon by means of a simple key-board.

What has been stated above in relation to an octave also applies with equal force to further octaves which it might be desired t give the instrument. It is quite easy to provide for an upper octave combined with the main octave in such a manner that all of the siren will be caused to rotate at a speed double that of the main octave.

One could, likewise, provide for a lower octave the cells of which could rotate at a speed half of that of the main octave adjacent to it. One could, finally have a bass octave the sirens of which would be rotate, at a speed half of that of the middle octave, i. e. four times slower than the speed of the main octave.

Having thus particularly described and ascertained the subject-matter of this presen'. invention and in What manner the same is to be performed, I declare that what I claim as new and desire to secure by Letters Patent, 18

1. In a musical instrument having a p11;- rality of octaves, the combination of six rotatable members for each octave, each member having two rows of openings containing respectively thirty-seven and forty-four orifices, and means for opening and closing th;

orifices o'f either row independently of those oi the other row, the individual members beinQ' in'tergea'red With 'eZLchother' so that" the ratio of rotation of the first, second, tlnrd,

fifth and sixth members With relation to the 'rotationfof the fourth member will herespectivejl'y 70'z'99 2212295, I 50 63, 196:185 a'ndi553'49. I

25111 e; musical instrument having a pluralityof octaves, the combination of six tone emitting members for each octave, each oi? V I said members comprising a stationary drum and a drum mounted for rotation Within said stationaryflrum, bo'thofsaicl drums having a pur of rows of openings contannng respectively thirty-seven and forty-four orifices,the

orifices of one'drumbeing aclapted'to register with those of the other drum, rings shiitably mounted on said stationary drum in encircling relation to each ofsaid rows ofopen ings, eachof said rings having orifices adagted to register'witlrthose oi the drum, said rings being shiftable to close the drum orifices, said tone 'emitting members being intergeared ith each other so that the ratio of rotation of the first second, third, fifth and sixth members With relation to the rotation of the fourthmember Will be respectively 7Q:99;2211295,50:63, 1'96: 185,'end 55 49.

In testimony whereof, I have signed my "name to this specificationnt the Hague, the

Netherlands, this 28th clayo'f August, 1929. ABRAHAM DIRK LOMAN, JUNIOR. 

